1. Field of the Invention
The present invention relates to a working unit, working device working a workpiece using mist generated by mixing air and cutting oil.
2. Description of the Related Art
Conventionally, in cutting work or grinding work, with respect to the method for supplying cutting oil (coolant) to a workpiece and a tool, there have been two kinds in general of a method of supplying the cutting oil through a space arranged inside a machine tool or a drilling unit (so-called center-through and spindle-through) and a method of supplying the cutting oil from a cutting oil supply unit arranged outside (so-called side-through and side fluid supply).
With respect to the center-through and spindle-through unit, two types are known, they are, one type blowing the foggy mist which is the mixture of the cutting oil and air to the tool and workpiece from behind the working unit in order to reduce friction, to lower the cost and the like, and another type respectively supplying the cutting oil and air from behind the working unit through the spindle and the outer periphery and the side of the spindle and blowing them to the tool and workpiece (for example, refer to Japanese Published Unexamined Patent Application Nos. 2006-316801 (refer to claim 1 and FIG. 1) and H11-320327 (refer to claim 1 and FIGS. 1, 2)).
Also, with respect to the side-through and side fluid supplying unit, a type connecting a cooling mist supply unit to the side of the tool at the leading end of the working unit in order to facilitate replacement of the tool, to improve working accuracy and the like and blowing the mist to the tool and workpiece is known (for example, refer to Japanese Published Unexamined Patent Application Nos. 2002-178207 (refer to claim 1 and FIG. 5) and 2008-207290 (refer to FIG. 1)).
However, in the past, in a drilling unit of a construction in which the center-through and spindle-through types could not be adopted, the side-through system was adopted. At that time, when there were a number of positions where the mist collided with the wall surface of the drilling unit, when the mist was hard to enter into a through-hole of a drill, or when the space volume inside a flow path where the mist flowed changed largely, there was a case that the mist was liquefied, the cutting oil accumulated inside, and only the air was ejected from the tip of the drill.
In this case, when a predetermined amount or more of the cutting oil was stored inside the drilling unit, there was a problem that the liquid of the cutting oil liquefied from the mist was intermittently discharged from the tip of the drill.